Description
Sullivantia hapemanii is a perennial herb with erect, glandular to hairy stems which stand 5-60 cm high. The basal leaves have petioles (stalks) which are usually much longer than the blades; the blades are 1-11 cm wide and kidney to circular shaped with 5-13 palmate lobes and sharply toothed margins. The few stem leaves are alternate, smaller than the basal leaves, and have short petioles. The flowers are borne in a glandular inflorescence with long spreading branches. The calyx is green, 1.5-3 mm long, and is bell-shaped with 5 triangular lobes. There are 5 separate white petals which are 1.2-5 mm long and are broad spatula-shaped and narrowed at the base. There are 5 short stamens and a single pistil which is about 1/2 buried in the hypanthium. The fruit is a dry, 2-celled, multi-seeded capsule, with axil placentation.
The two varieties can be distinguished by measurable differences in the appearance of the ovary at anthesis and mature fruiting capsules. In var. hapemanii the ovary is about as long as it is wide; while in var. purpusii the ovary is usually about twice as long as it is wide. The fruit of var. hapemanii is an ovate cylindrical capsule less than 2.5 times (usually ca 2 times)longer than broad at maturity.; in contrast the fruit of var. purpusii is long and cylindrical, and is very narrow in relation to its width, at least 2.5 times longer than broad at maturity (Soltis 1991).
Diagnostic Characteristics
This is the only species of its genus in Montana. It is distinguished from other members of the Saxifrage family by having flowers with 5 stamens, a 2-celled ovary with axil placentation, and the calyx and petal dimensions of 1.5-3 mm and 1.2-5 mm, respectively. White flowers, five stamens, an open and erect inflorescence usually with branches perpendicular to stem, and lobed basal leaves with entire or erose margins distinguish var. hapemanii from other similar species in its range (Fertig 1993).
Habitat
This species is found in moist-wet locations, such as moist cliffs near water, usually in association with calcareous rock outcrops.
Var. hapemanii is found scattered throughout mesic limestone/dolomite canyons from 3,700 to 7,400 feet in elevation, on various aspects and slopes ranging from 0 - 90 degrees, in association with ferns and mosses. In Wyoming, it is restricted to moist - wet calcareous outcrops and boulders along streams and, generally, in well-shaded places, and sites appear to be dependent on high moisture or humidity (Fertig 1993). On the Bighorn National Forest, many, but not all, of the populations are found on mossy substrate (Michele Girard, personal communication, November 1995). However several occurrences have recently been recently observed in dry canyons and canyons with intermittent streams (personal observation). In Idaho, Bob Moseley reports that var. hapemanii has been found on wet granite outcrops associated with waterfalls or dripping water (Fertig 1993).
Var. purpusii is found "in very specialized habitat" such as wet dripping cliffs, moist canyon walls and in close proximity to waterfalls, (Soltis 1991), and on overhangs, permanently wet cracks and crevices, and on Northeast to Northwest slopes or microsites at elevations ranging from 6,500 to 10,000 feet, sometimes associated with a rare columbine (aquilegia barnebyi)(Nyborg 1979). It is found growing on limestone, shale, and quartzite cliffs (Susan Spackman, Colorado Natural Heritage Program, personal communication, December 1995).
Ecology
Population/occurrence size is highly variable; in some areas in Wyoming var. hapemanii occurs as isolated patches (subpopulations) of several to several thousand; (Marriot & Jones 1989).
Reproduction is by seed; the species is not stoloniferous (Soltis 1991). Var. hapemanii plants flower and fruit from June to August, with fruiting sometimes continuing to mid-September (Fertig 1993). Var. purpusii flowers from mid June to late July, and fruits from July to August.